Rear curtain sync from the hotshot/pc sync?

[MattBW]

More a still feature but I wondered if it was feasible to allow rear curtain sync other than the built in flash or a canon flash on the hotshoe. Any off camera flash photographer will at some point want rear curtain.

The lack of rear curtain sync via the hotshot/pc sync port has frustrated me for years with Canon. I even spoke to them directly and they said it would never be added.